Thanks for the help! The engine had sputtered out several times because (I think) the squeeze bulb in the line wasn't functioning properly. Once I got it coughing I gunned it for shore, it stalled again in gear, and there she stuck.
Back off the throttle, and check the shifter linkage, I've seen the linkage bind up and get stuck in gear on quite a few tiller rigs in my day. Don't know about yours specifically but some units linkage for the neutral safety can get jammed up too.
